LAUSR

Graphical abstract Figure. No Caption available. HighlightsFirst IL‐DLLME method for determination of cortisone and cortisol in saliva.The method provides high selectivity and enrichment factors to achieve biological levels.The IL enables extraction and concentration of cortisone and cortisol in one step.The method needs no sophisticated instrumentation and is environmentally friendly. Abstract Ionic liquid dispersive liquid–liquid microextraction (IL‐DLLME) was used for the first time for the extraction and preconcentration of cortisone and cortisol from human saliva samples. This approach allows the determination of both compounds by liquid chromatography (LC) with ultra‐violet/visible (UV/Vis) detection at physiological levels. The IL 1‐butyl‐3‐methylimidazolium hexafluorophosphate [C4MIM][PF6] and methanol (MeOH) were used as extraction and dispersive solvents, respectively. The parameters that affect extraction (ionic strength, pH, amount of IL, volume of dispersive solvent, vortex and centrifugation time) were optimized. Limits of detection were 0.11 (cortisone) and 0.16 &mgr;g L−1 (cortisol) and enrichment factors of 5.0 (cortisol) and 6.3 (cortisone) were achieved. Recoveries from 83.3 ± 1.6 to 115.8 ± 3.0% were obtained for the extraction of the target analytes in spiked human saliva samples. Intraday and interday precision, expressed as relative standard deviation, was below 4.2 and 7.8% for cortisone and cortisol, respectively. The method was successfully applied to the determination of cortisone and cortisol in saliva from healthy volunteers (n = 9) in the morning and in the evening. The method is simple, faster, and more environmentally friendly than the current ones.